Studies were directed toward determining the nature and mechanism of circulating and cellular immune responses to antigenic challenges in animals and humans, including patients with abnormal immunologic responses such as gluten-sensitive enteropathy, dermatitis herpetiformsi (DH), and inflammatory bowel disease. In addition, studies were directed to determining the mechanism of disease in various immunodeficiency states such as ataxia telangiectasia, hypogammaglobulinemia and intestinal lymphangiectasia. Insight into the cause of the high incidence of reticuloendothelial malignancies associated with these disorders were sought.